PITTSBURGH — The Bruins were seven minutes away from stealing a win. They held a 2-0 lead over the Penguins. Anton Khudobin was making timely saves. Zdeno Chara had kept Sidney Crosby (20 points in his last eight games) off the scoresheet.

But the Bruins were sitting on their lead. It is no way to play against any opponent, far less one as lethal as Pittsburgh. The Penguins made the Bruins pay for their indifference.

In just 4:15 of third-period play, the Bruins watched a 2-0 win explode into a 3-2 kick-to-the-teeth loss before 18,640 at the Consol Energy Center.

“Some really, really bad decision-making led to those goals,” said coach Claude Julien. “It’s of our own doing. We gave them that game when we had control of it.”

A multi-goal lead in the third period used to be the equivalent of a lights-out sleeper hold for the Bruins. But the Bruins are a pedestrian 7-3-1 in games when they’ve led after 40 minutes. On Tuesday, for the second time in a week, they watched a third-period advantage turn into a loss.

“They were able to build the game and score three goals in the last seven minutes,” Milan Lucic said. “It [stinks]. We’ve got to learn from it again. It’s happened to us too many times where we’ve blown leads going into the third period.”

Marc-Andre Fleury saw only 16 pucks come his way. The Bruins put just four shots on goal in the third. Instead of being aggressive and controlling the play, the Bruins gave the Penguins far too many attacking opportunities and time with the puck in their zone.

Puck management, usually one of the Bruins’ strengths, was their undoing. The Penguins finally busted through on Khudobin at 13:42 of the third. But it came only after Chris Kunitz picked off Johnny Boychuk’s clearing attempt up the wall.

As the Penguins snapped the puck around the perimeter, Kunitz floated to the right circle and opened up for a one-timer, eluding the Bruins’ coverage. After taking a cross-ice pass from Kris Letang, Kunitz hammered the puck past Khudobin to make it a 2-1 game. Khudobin had pushed over to stay square to Kunitz, but he couldn’t stop the shot.

“Every goal is possible to save,” Khudobin said. “I could stop the first, second, and third. It was a great play. You can’t say they just scored easy goals. They were good goals. But I think you can stop any of them.”

Less than a minute later, Brandon Sutter scored the first of his two goals. Sutter started the play at the red line by winning a puck battle against Lucic. Sutter gave the puck to Beau Bennett, who sprinted over the offensive blue line to trigger a three-on-two rush against Andrew Ference and Adam McQuaid. Before the defensemen could close on Bennett, the forward dished to James Neal. In turn, Neal flipped a backhander to Sutter, who whipped the puck past Khudobin at 14:33 of the third to tie the game at 2-2.

“We didn’t gap up quick enough,” Dennis Seidenberg said. “That gave them a lot of speed to attack us and get pucks to the net.”

Sutter capped the rally at 17:57 of the third. The Bruins were in good shape on the play. Boychuk and Seidenberg had successfully fended off a Crosby rush.

Seidenberg controlled the puck and looked to initiate the counterattack. Nathan Horton was turning up the ice on the right wing. Seidenberg attempted a long-distance cross-ice pass to Horton. But Sutter read the play and stepped in front of Seidenberg’s pass. With a whip-like shot, Sutter flung the puck through Khudobin for the winner.

“Third goal, 2-2 tie, it’s the kind of shot you could save and it would be 2-2 in overtime,” Khudobin said.

The third-period fold job wiped out a hard-charging opening 20 minutes. The Bruins, coming off Monday’s 3-2 shootout win over Ottawa, had fresh legs in the first period. At 4:45, Chara hammered a power-play one-timer through Fleury, with help from a Bergeron screen.

At 13:30, Bergeron helped set up another goal. Brad Marchand sent a puck down the wall for Bergeron behind the Pittsburgh net. As Bergeron emerged from the corner with the puck, Tyler Seguin cut to the front of the net. Seguin reeled in Bergeron’s pass and snapped a shot upstairs on Fleury to give the Bruins a 2-0 edge.

Skating, smart decisions, and overall sharpness gave the Bruins their two-goal lead.

For parts of the second period and most of the third, the Bruins had none of those assets going their way.

“We were making flat passes, moving it up quick, getting it in, doing the simple things that gave us success in the first period,” said Boychuk. “In the third period, we started to do things differently — not getting pucks in deep, a lot of turnovers, not doing the things we were doing in the first period. It led to some turnovers. And eventually the game.”